This invention relates to a soil pesticide composition. More particularly the invention relates to a liquid composition useful as a nematocide.
Many compounds have been used as nematocides for cropland soils. It is preferred to use compounds that can be applied as liquid solutions that can soak into soils as opposed to application of dry compositions which can be blown away by the wind.
One such compound is tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (hereinafter referred to as TDTT), sold under the trademark xe2x80x9cDazometxe2x80x9d by Verichem Inc. TDTT is not very soluble or stable in commonly used agricultural solvents or carriers, and is typically applied in granular form. Where it is applied as a liquid formulation its concentration is limited to less than 15% by weight.
It would be very useful to be able to deliver TDTT to the soil as a stable solution and in concentrations greater than 15% by weight.
It is an object of this invention to provide a composition of TDTT in an environmentally acceptable solvent at concentrations greater than about 15% by weight for use as a soil pesticide, and particularly as a nematocide.
The pesticide composition of the present invention is comprised of TDTT, a first co-solvent of 1,3-dichloropropene (1,3-D), and a second co-solvent that is an aprotic polar organic solvent, such as dimethyl sulfoxide (DMSO) or dimethylformamide (DMF), where the TDTT is present in an amount greater than about 15% by weight of the composition.
The pesticidal composition of the present invention comprises between about 15% and about 35% by weight TDTT, between about 25% and about 45% by weight 1,3-D as a first co-solvent, and between about 25% and about 50% by weight of an aprotic polar organic solvent as a second co-solvent, the second co-solvent preferably being selected from the group consisting of DMSO and DMF.
Small amounts of surfactants, up to about 5% by weight of the composition, may be used to maintain TDTT solubility over a wide range of temperatures. Suitable surfactants include, but are not limited to, polyethylene glycols or tergitols.
One of the surprising benefits of this invention is in discovering that 1,3-D acts as a solvent for TDTT. 1,3-D, which is sold under the trademark xe2x80x9cTelonexe2x80x9d by DowElanco is itself a known pesticide, although at the concentrations employed in the composition of the present invention, i.e., at an effective application level of less than about 15 gallons per acre, it would not by itself exhibit pesticidal activity.
The liquid pesticide compositions of this invention are applied to the soil to be treated at a rate effective to control pest infestation, preferably at a rate of about 10 to about 20 gallons per acre.